Interlocking building cube



FIG. 1 is a front perspective view;

FIG. 2 is a rear perspective view;

FIG. 3 is a right side perspective view;

FIG. 4 is a left side perspective view;

FIG. 5 is a top plan view;

FIG. 6 is a bottom plan view; and,

FIG. 7 is a front perspective of my design shown in use.

The broken lines shown in FIG. 7 is for illustrative purposes only and form no part of the claimed design. 

The ornamental design for interlocking building cube, as shown and described. 